Abstract
The present study was carried out to investigate the development of bovine embryos fertil-ized in vitro up to blastocyst using CRlaa medium.
The cumulus free in vitro fertilized ova were randomly assigned to 6 groups and then these were cul-tured for 7 days. The groups were 1) CRLaa; 2) CR1aa+ 5 % calf serum (CS) ; 3) CRLaa+ 5% CS+bovine oviductal epithelial cells (OVC) ; 4) TCM-199; 5) TCM-199+ 5% CS; and 6) TCM-199+ 5% CS+OVC.
For the 6 groups, developmental rates (24.1 and 22.1%) of embryos cultured in CRlaa+ 5 % CS and CRlaa+ 5 % CS+OVC up to blastocyst stage were higher (P<0.05) than the other culture systems. The total cell numbers of embryos cultured in CRlaa+ 5 % CS and CRlaa+ 5 % CS+OVC at blastocyst stage were 100.1 ± 27.7 and 97.2 ± 31.4, respectively, and there is no significant difference.
In conclusion, our experiment clearly demonstrated that CRlaa require serum nutrients for development of cumulus free early bovine embryos to blastocyst stage, and that CR1aa+ 5 % CS is beneficial in the development in vitro under the condition of the absence of co-culture with oviductal epithelial cells.
